New model for this year (Do not check this option if this model was listed as new in last year's Gear Guide)The ACT ZERO was designed and built with lighter, faster, thru-hikers and versatility in mind. These packs allow the experienced backpacker, hiker and mountaineer to carry all the necessities without added pack weight. AIRCONTACT back system reduces perspiration by 15% and heat build up. Removable lid with +15L resupply extension collar, adjustable shoulder harness, large compressing stuff-it pocket, hollow core Aluminum X stays, ice axe and trekking pole loops, top and bottom lid pockets, mesh side pockets, hip belt pocket.